Presently, the already-known bending machines and apparatus for bending rods and the like are numerous, giving solutions more or less mechanized and automatic. But all the known highly mechanized machines are principally designed to specific fields of employment and their use being specific, their versatility is remarkably reduced.
A notable level of mechanization and automation is shown by the stirrup machines. But they aren't suitable to bend rods as to obtain forms of big sizes. They are designed to bend progressively the rod during its feed so to accomplish its bending and to cut the form obtained, which usually has a small size (e.g.:stirrups).
To obtain big-sized shapes special apparatuses have been built, like the one of the Italian Pat. No. 976700 (filed on Feb. 16, 1973) in the name of the same inventor, corresponding to G.B.-Pat. No. 1435 033, Swiss-Pat. No. 573 273, French-Pat. No. 74038350. Considering said patent, the necessity to bend big shapes is fulfilled by bending long rods employing two-rod bending machines disposed on track means in spaced relationship to each other so to be movable towards and away from each other. Such a solution requires a high cost of operation. Moreover, this way shapes with very short sides are obtained with a certain difficulty.
As a matter of fact, it is difficult, to obtain shapes having short sides also when using traditional bending or stirrup machines as they always have feed means placed upstream the bending unit itself. Furthermore, the known machines having rod-feed units cannot perform bendings which are over the theoretical 180.degree.. The known bending methods most of the time lead to the production of shapes which don't lie entirely on the same plane because of the anisotropy of the material and of the non-perfect symmetry of the bending means.